THE ENDOCRINE AKA HORMONAL SYSTEM
WHAT IS THE ENDOCRINE SYSTEM?
The Endocrine System is in charge of body processes that happen slowly such as
cell growth. The Endocrine System influences almost every cell and organ of the body. The endocrine system is instrumental
in regulating;
1) Growth & Development.
2) Metabolism.
3) Reproductive Processes.
4)
Sexual Function.
5) Tissue
Function.
The foundations of the Endocrine Systems are the hormones and glands.
A gland is a group of cells that produces and secretes chemicals. A gland selects and removes materials from the blood, processes
them and secretes the finished chemical product for use somewhere in the body. Some types of glands release their secretions
in specific areas. For Example;
1) Exocrine
Glands (Release secretions in the skin or inside the mouth).
2)
Endocrine Glands (Release hormones directly into the bloodstream).
MAJOR GLANDS THAT MAKE UP THE ENDOCRINE
SYSTEM
1) Hypothalamus Gland.
2) Pituitary Gland.
3)
Pineal Gland.
4) Thyroid
Gland.
5) Parathyroid Gland.
6) Thymus.
7)
Adrenal Gland.
8) Pancreas
Gland.
9) Ovary Gland.
10) Testes Gland.
Once a hormone
is secreted, it travels from the endocrine gland that produced it through the bloodstream to the cells (known as target cells)
designed to receive its message. Along the way to the target cells, special proteins bind to some of the hormones.
These proteins act as carriers that control the amount of hormones that is available for the cells to use. The target cells
have receptors that latch onto only specific hormones and each hormone has its own receptor so that each hormone will communicate
only with specific target cells that have receptors for that hormone. When the hormone reaches its target cell it locks onto
the cell’s specific receptors and these hormone-receptor combinations treansmit chemical instructions to the inner workings
of the cell.
When hormone levels reach a certain normal amount, the endocrine system helps the body to
keep that level of hormone in the blood. For example;
“If the thyroid gland has secreted
the right amount of thyroid hormones into the blood, the pituitary gland senses the normal levels of thyroid hormone in the
bloodstream. Then the pituitary gland adjusts its release of thyrotropin, the hormone that stimulates the thyroid gland to
produce thyroid hormones.”
The Hypothalamus Gland is a collection of specialized cells that is located
in the lower central part of the brain and is the main link between the endocrine and nervous system. The
hypothalamus gland regulates homeostasis or balance in the body. Nerve cells in the hypothalamus control the pituitary
gland by producing chemicals that either stimulate or suppress hormone secretions from the pituitary.
The
Pituitary Gland which is the size of a pea is located at the base of the brain just beneath the hypothalamus gland is considered
the “Master Gland” because it makes hormones that control several other endocrine glands. The production
and secretion of pituitary hormones can be influenced by factors such as emotions and changes in the seasons. To accomplish
this, the hypothalamus gland provides information (such as environmental temperature, feelings and light exposure patterns)
sensed by the brain to the pituitary.
THE HYPOTHALAMUS
The Hypothalamus secretes Thyrotropin Releasing
Factor causing the anterior pituitary to secrete thyroid stimulating hormone.
The Hypothalamus secretes Gonadotropin Releasing Factor
causing the anterior pituitary to secrete follicle stimulating and luteinizing hormones.
The Hypothalamus secretes Corticotropin Releasing Factor
causing the anterior pituitary to secrete corticotropin hormone.
The Hypothalamus secretes Growth Hormone Releasing Factor causing the
anterior pituitary to secrete growth hormone.
The Hypothalamus secretes Somatostatin Releasing Factor causing the anterior pituitary
to secrete a hormone ihibiting the release of growth hormone.
The Hypothalamus secretes Prolactic Inhibiting Releasing Factor causing
the anterior pituitary to secrete a hormone that can inhibit or stimulate the secretion of prolactin.
The Hypothalamus secretes Gastrointestinal Neuropeptides
which stimulates the secretion of pancreatic juices in the gastro intestinal tract.
THE ANTERIOR PITUITARY
The Anterior
Pituitary secretes the Growth Hormone which causes normal growth rate and maintains proper energy levels.
The Anterior Pituitary secretes the Prolactin Hormone which stimulates
milk production (breast feeding).
The Anterior
Pituitary secretes the Adrenocorticotropic Hormone which stimulates the adrenal gland (fight/flight).
The Anterior Pituitary secretes the Thyroid Stimulating Hormone
which stimulates the thyroid gland (metabolism).
The Anterior
Pituitary secretes the Follicle Stimulating Hormone which stimulates the ovaries (females) and testes (males).
The Anterior Pituitary secretes the Luteinizing Hormone
which also stimulates the ovaries (females) and testes (males).
THE MIDDLE PITUITARY GLAND
The Middle Pituitary secretes the Hormone Melanocyte
to control skin pigmentation.
THE POSTERIOR PITUITARY GLAND
The Posterior Pituitary secretes the Hormone
Antidiuretic to increase water into the blood.
The Posterior Pituitary secretes the Hormone Oxytocin to contract the
uterus during labor.
THE PINEAL GLAND
The Pineal secretes the Hormone Melatonin
to induce sleep.
THE THYROID GLAND
The Thyroid secretes the Hormone Iodine
to synthesize T3 & T4.
The
Thyroid secretes the Hormone Thiodothyronine
to increase cell metabolism.
The Thyroid secretes Thyroxine (T4)
increases cell metabolism.
The
Thyroid secretes Calcitonin for calcium &
phosporous metabolism.
THE PARATHYROID GLAND
The Parathyroid secretes the Hormone Parathyroid
to control calcium & phosporous control.
THE THYMUS GLAND
The Thymus
secretes the Hormone Thymopoietin to produce T-Cells and help fight infection.
The Thymus secretes the Hormone Thymosis to produce T-Cells and help fight infection.
THE ADRENAL CORTEX GLAND
The
Adrenal Cortex secretes the Hormone Hydrocortisone aka Cortisol to control carbohydrates, fats and proteins.
The Adrenal Cortex
secretes the Hormone Corticosterone to suppresses
inflammation.
The
Adrenal Cortex secretes the Hormone Aldosterone to inhibits sodium in urine.
The Adrenal Cortex secretes the Hormone Aldosterone
to maintain blood pressure.
The
Adrenal Cortex secretes the Hormone Aldosterone to maintain blood volume.
The Adrenal Cortex secretes the Hormone Androgen aka Androgenic Steroids to develop male characteristics.
THE ADRENAL MEDULLA GLAND
The
Adrenal Medulla secretes the Hormone Epinephrine aka Adrenaline to increase heart rate.
The Adrenal Medulla secretes the Hormone
Epinephrine aka Adrenaline to increase the force of heart contractions.
The
Adrenal Medulla secretes the Hormone Epinephrine aka Adrenaline to facilitates blood flow.
The Adrenal Medulla secretes the Hormone Epinephrine
aka Adrenaline to relax smooth muscles.
The Adrenal Medulla secretes the Hormone Epinephrine aka Adrenaline to convert
glycogen to glucose.
The
Adrenal Medulla secretes the Hormone Nor-Epinephrine aka Nor-Adrenaline which causes strong vasoconstrictive
effects.
THE PANCREAS GLAND
The Pancreas secretes the
Hormone Insulin to force many cells of the body to absorb and use glucose thereby decreasing blood sugar.
The Pancreas secretes the Hormone Glucagon
to force many cells of the body to release or produce glucose thereby increasing blood sugar.
The Pancreas secretes the Hormone Gastrin to induce
acid producing cells of the stomach to produce acid.
The Pancreas secretes the Hormone Somatostatin to slow down production
of insulin, glucagon and gastrin.
The
Pancreas secretes the Hormone Vasa Active Intestinal Peptide (VIP) which causes the intestinal cells to secrete
water and salts into the intestines which inhibits absorption.
THE OVARIES GLAND
The
Ovaries secretes the Hormone Estrogen which causes female sex characteristics.
The Ovaries secretes the Hormone Estrogen which causes
thickening of the endometrium (uterus).
The Ovaries secretes the Hormone Estrogen which regulates the menstrual cycle.
The Ovaries secretes the Hormone Progesterone
which stabilize the tissue lining of the endometrium (uterus).
The Ovaries secretes the Hormone Progesterone prevents heavy menstrual
bleeding.
The Ovaries
secretes the Hormone Esttradiol which is the major estrogen in females.
THE TESTES GLAND
The
Testes secretes the Hormone Testosterone which increases muscle mass.
The Testes secretes the Hormone Testosterone which deepens
the voice.
The Testes
secretes the Hormone Testosterone which causes adult type body odor.
The Testes secretes the Hormone Testosterone which increases
libido (sex drive).